From patchwork Sat Dec 21 09:48:02 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thorsten Blum X-Patchwork-Id: 13917763 Received: from out-179.mta1.migadu.com (out-179.mta1.migadu.com [95.215.58.179]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CEC423F9D2 for ; Sat, 21 Dec 2024 09:49:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.179 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734774543; cv=none; b=NgSmvIJSSaXuh3s7KqejuF7HVQW6GCfhWU4Udn6S52pRKKq/BuPUy0KVarnKbJFBNE8DjLHotRel+M+lEXDvU09Bahoe0PAisZN04b47PJWDQ/DiXCx42ZV6G7vfxsOPfkoE6l3f7pTOuAi+3dBZZGVV69rz1Sl+mJa7rGIcHTU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734774543; c=relaxed/simple; bh=cmVb76fr41h+B8X6CVyACIA8cA6pC9xqC9/Perks9Tw=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=mD6IMImJkykZxLY9sej6RFFnf+i1Qg/lnLUuPICSBAisL6HQuI5bLvvox9bUqpHMBnCVgUslCCroWrSDVk2szjbZuzueALCqOaxSMeeMuOUZplD/KWLC0T8Fg82+qP9SYcSCJ5Vqx2OqcEt2KhJI9FptwoBc6u4ABtnjcvmatXk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=NCL8/xdQ; arc=none smtp.client-ip=95.215.58.179 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="NCL8/xdQ" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1734774538; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=/krp34iAvyquzhaabUgMh39+FlbVT/TCY2R0VKeKZU4=; b=NCL8/xdQq5s8ufIkJYtQj4L5aSCVne4wH0qkElLDMqjKcQuhRUJfmcjY/TcWF1v2OTXZUu IIeg+59Yx20/l563oVyjpo09UB47KVO0pnkhz8qQjOwS6GluzCuuvugyGb+ZKbJMgpiuVe QeuKf7ZQvSbmenZuTejxE9wjyBhcogE= From: Thorsten Blum To: Kees Cook , "Gustavo A. R. Silva" Cc: andriy.shevchenko@linux.intel.com, mcgrof@kernel.org, Thorsten Blum , linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org Subject: [RESEND PATCH v2] params: Annotate struct module_param_attrs with __counted_by() Date: Sat, 21 Dec 2024 10:48:02 +0100 Message-ID: <20241221094803.5329-2-thorsten.blum@linux.dev> Precedence: bulk X-Mailing-List: linux-hardening@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT Add the __counted_by compiler attribute to the flexible array member attrs to improve access bounds-checking via CONFIG_UBSAN_BOUNDS and CONFIG_FORTIFY_SOURCE. Increment num before adding a new param_attribute to the attrs array and adjust the array index accordingly. Increment num immediately after the first reallocation such that the reallocation for the NULL terminator only needs to add 1 (instead of 2) to mk->mp->num. Use struct_size() instead of manually calculating the size for the reallocation. Use krealloc_array() for the additional NULL terminator. Signed-off-by: Thorsten Blum --- Changes in v2: - Use krealloc_array() as suggested by Andy Shevchenko - Link to v1: https://lore.kernel.org/r/20240823123300.37574-1-thorsten.blum@toblux.com/ --- kernel/params.c | 29 +++++++++++++---------------- 1 file changed, 13 insertions(+), 16 deletions(-) diff --git a/kernel/params.c b/kernel/params.c index 2e447f8ae183..5f6643676697 100644 --- a/kernel/params.c +++ b/kernel/params.c @@ -551,7 +551,7 @@ struct module_param_attrs { unsigned int num; struct attribute_group grp; - struct param_attribute attrs[]; + struct param_attribute attrs[] __counted_by(num); }; #ifdef CONFIG_SYSFS @@ -651,35 +651,32 @@ static __modinit int add_sysfs_param(struct module_kobject *mk, } /* Enlarge allocations. */ - new_mp = krealloc(mk->mp, - sizeof(*mk->mp) + - sizeof(mk->mp->attrs[0]) * (mk->mp->num + 1), + new_mp = krealloc(mk->mp, struct_size(mk->mp, attrs, mk->mp->num + 1), GFP_KERNEL); if (!new_mp) return -ENOMEM; mk->mp = new_mp; + mk->mp->num++; /* Extra pointer for NULL terminator */ - new_attrs = krealloc(mk->mp->grp.attrs, - sizeof(mk->mp->grp.attrs[0]) * (mk->mp->num + 2), - GFP_KERNEL); + new_attrs = krealloc_array(mk->mp->grp.attrs, mk->mp->num + 1, + sizeof(mk->mp->grp.attrs[0]), GFP_KERNEL); if (!new_attrs) return -ENOMEM; mk->mp->grp.attrs = new_attrs; /* Tack new one on the end. */ - memset(&mk->mp->attrs[mk->mp->num], 0, sizeof(mk->mp->attrs[0])); - sysfs_attr_init(&mk->mp->attrs[mk->mp->num].mattr.attr); - mk->mp->attrs[mk->mp->num].param = kp; - mk->mp->attrs[mk->mp->num].mattr.show = param_attr_show; + memset(&mk->mp->attrs[mk->mp->num - 1], 0, sizeof(mk->mp->attrs[0])); + sysfs_attr_init(&mk->mp->attrs[mk->mp->num - 1].mattr.attr); + mk->mp->attrs[mk->mp->num - 1].param = kp; + mk->mp->attrs[mk->mp->num - 1].mattr.show = param_attr_show; /* Do not allow runtime DAC changes to make param writable. */ if ((kp->perm & (S_IWUSR | S_IWGRP | S_IWOTH)) != 0) - mk->mp->attrs[mk->mp->num].mattr.store = param_attr_store; + mk->mp->attrs[mk->mp->num - 1].mattr.store = param_attr_store; else - mk->mp->attrs[mk->mp->num].mattr.store = NULL; - mk->mp->attrs[mk->mp->num].mattr.attr.name = (char *)name; - mk->mp->attrs[mk->mp->num].mattr.attr.mode = kp->perm; - mk->mp->num++; + mk->mp->attrs[mk->mp->num - 1].mattr.store = NULL; + mk->mp->attrs[mk->mp->num - 1].mattr.attr.name = (char *)name; + mk->mp->attrs[mk->mp->num - 1].mattr.attr.mode = kp->perm; /* Fix up all the pointers, since krealloc can move us */ for (i = 0; i < mk->mp->num; i++)